Something

import java.util.ArrayList;
public class Hotel {

   /** Creates a new instance of Hotel */
   public Hotel() {
   }
   private Reservation rooms[];
   private ArrayList waitList;

   public Reservation requestRoom(String name){
           for(int i = 0; i < rooms.length; i++){
               //if there is an empty room, make the reservation
               if(rooms[i] == null){
                   Reservation res = new Reservation(name, rooms[i]);
                   return res;
               }
               Return null;
           }
           //add name to waitlist and return null if there are no rooms
           waitList.add(name);
           return null;
   }
   public Reservation cancelAndReassign(Reservation res){
       int roomNumber = res.getRoomNumber();
       for(int i = 0; i < rooms.length; i++){
           if(rooms[i] == roomNumber){
               if(!waitList.isEmpty()){
               Reservation newRes = new
Reservation(waitList.remove(), rooms[i]);
               return newRes;
               }
               else{
                   room[i] = null;
                   return null;
               }
           }
       }
   }